Foxboro FBM218: I/A Series FBM Communication Redundant Output Interface Module –

Technical Dossier

Product Details And Specifications

Foxboro FBM Series: Comprehensive Module Range and Technical Overview

The Foxboro FBM (Fieldbus Module) series forms the I/O backbone of the Foxboro I/A Series Distributed Control System (DCS), one of the most widely deployed process automation platforms in global heavy industry. Installed across petrochemical complexes, nuclear power stations, offshore oil platforms, crude oil refineries, and large-scale chemical processing facilities, the FBM series provides the critical interface layer between field instrumentation and the I/A Series control network. The FBM218 specifically serves as a Communication Redundant Output Interface Module, enabling fault-tolerant signal transmission in high-availability process loops where unplanned downtime carries significant operational and safety consequences. Foxboro I/A Series installations remain active at hundreds of sites worldwide, many of which have been in continuous operation for 20+ years, creating sustained demand for FBM spare parts and lifecycle support.

The Evolution of FBM Architecture

The FBM series was introduced alongside the Foxboro I/A Series DCS in the mid-1980s, representing a modular, distributed I/O philosophy that was architecturally ahead of its time. Early FBM generations (FBM01–FBM10) handled basic analog and discrete I/O over the Nodebus communication infrastructure. As process industries demanded higher channel density, redundancy, and fieldbus compatibility, Foxboro expanded the catalog through successive generations.

The mid-generation FBMs (FBM100–FBM220 range) introduced support for HART communication, redundant module configurations, and enhanced diagnostic capabilities. The FBM218 belongs to this mature generation, designed specifically for redundant output interfacing — a critical requirement in safety-instrumented loops and high-uptime process units. Later additions to the FBM catalog addressed FOUNDATION Fieldbus (FF) and PROFIBUS PA integration, extending the I/A Series into modern fieldbus topologies without requiring full system replacement.

Compatibility across FBM generations is governed by the I/A Series Nodebus and Fieldbus Module Processor (FMP) architecture. Mixing early and late-generation FBMs within the same FBM Enclosure requires careful firmware and FMP version verification. Sites upgrading from legacy FBM configurations to current-generation equivalents must validate backplane slot assignments and module addressing to avoid communication conflicts.

FBM Full Catalog & Functionalities (SKU List)

The following represents a structured reference index of the Foxboro I/A Series FBM catalog, organized by functional category. All SKUs listed are verified members of the FBM series.

Analog Input Modules

• FBM201: 8-channel analog input, 4–20 mA, HART-compatible, single-ended
• FBM202: 16-channel analog input, 4–20 mA, non-HART, high-density configuration
• FBM203: 8-channel analog input with redundant module support, HART pass-through
• FBM204: Thermocouple/RTD input module, 8-channel, multi-sensor type support
• FBM207: 8-channel analog input, isolated, for high-noise industrial environments

Analog Output Modules

• FBM211: 8-channel analog output, 4–20 mA, standard single configuration
• FBM212: 8-channel analog output, HART-compatible, loop-powered
• FBM214: 4-channel analog output, high-accuracy, for precision control loops
• FBM217: 8-channel analog output, redundant-capable, pre-FBM218 generation
• FBM218: Communication redundant output interface module; provides fault-tolerant AO signal path with automatic switchover for critical process loops

Digital Input Modules

• FBM220: 32-channel digital input, 24 VDC, high-density discrete sensing
• FBM221: 16-channel digital input, isolated, for high-voltage field signals
• FBM224: 32-channel digital input, 120 VAC compatible, plant-floor signal interfacing

Digital Output Modules

• FBM230: 16-channel digital output, 24 VDC, solid-state switching
• FBM232: 8-channel digital output, relay contact, for high-current actuator control
• FBM237: 16-channel digital output, redundant configuration, safety-loop compatible

Communication & Specialty Modules

• FBM240: FOUNDATION Fieldbus H1 interface module, 2-segment capacity
• FBM241: PROFIBUS PA interface module, multi-drop field device support
• FBM242: HART multiplexer interface, 16-channel HART device management

Sourcing Hard-to-Find & Obsolete FBM Series Parts

The Foxboro I/A Series DCS entered its mature/end-of-active-development phase following Schneider Electric's acquisition of Foxboro (via Invensys). While Schneider Electric continues to offer limited support under the EcoStruxure Foxboro DCS brand, many FBM modules — particularly those in the FBM200–FBM220 range — have been discontinued from active production. Lead times through OEM channels for these modules can extend to 6–18 months, or parts may be declared permanently unavailable.

DriveKNMS maintains a dedicated inventory of tested, refurbished, and new-surplus FBM modules to support sites requiring lifecycle extension beyond OEM support windows. Our sourcing network covers the full FBM catalog, including low-volume specialty modules such as the FBM218, FBM207, FBM241, and FBM242. For sites operating under long-term maintenance contracts or preparing for planned turnarounds, DriveKNMS can provide consignment stock arrangements and advance procurement to eliminate unplanned downtime risk.

Quality Control for the FBM Series Range

FBM modules present specific testing challenges due to their integrated backplane communication logic, HART signal conditioning circuits, and — in redundant models such as the FBM218 — active switchover relay and dual-channel output verification requirements. DriveKNMS applies a structured test protocol to all FBM units prior to dispatch:

• Backplane connector inspection and pin continuity verification against Foxboro FBM mechanical specifications
• Nodebus communication handshake test using I/A Series-compatible test bench hardware
• Channel-by-channel analog signal accuracy verification (input/output linearity, offset, and span)
• HART communication layer validation for HART-enabled modules (FBM201, FBM203, FBM212, FBM242)
• Redundancy switchover simulation for dual-module configurations (FBM218, FBM217, FBM237)
• Firmware version identification and documentation for compatibility reporting
• 48-hour burn-in cycle under simulated load conditions prior to final QC sign-off

All tested units are shipped with a DriveKNMS inspection certificate and 12-month warranty against functional defects.